Animal Electrocution

As managing director of Boston's Animal Rescue League, Huntington Smith 1887 had no choice but to do away with the sick and homeless dogs, cats, and horses that made their way to his shelter. In 1911 he patented the "Automatic Electric Cage," a large device that administered a lethal shock. Considered safe and humane, the cage was quickly purchased by shelters in more than 40 cities; profits from sales went to the Boston League.

A second Smith invention: muzzle prints for dogs. Discovering that canine noses, like human fingers, leave unique prints, he devised a printing and record-keeping system to help track down lost pets.